The Overlap Between Eating Disorders and Autism

In my work as a dietitian, I often come across patients who are suffering from anorexia nervosa and eating disorders such as avoidant/restrictive food intake disorder (ARFID). When we mention eating disorders, the assumption is usually that the person is scared of gaining weight. However, in someone with Autism Spectrum condition (ASC) it can equally be about a fear of the numbers being different or fear of change itself. Therefore, the treatment for someone who is neurotypical with an eating disorder is very different from the treatment for those who are maybe neuro-atypical and have autism. Using the usual treatments for eating disorders with someone who is neuro-atypical can be unhelpful, and at the worst harmful, leaving them feeling fearful and traumatised . That is why it’s vital the correct diagnosis is given so the treatment can be adapted. In my experience, patients who find that normal treatments for eating disorders don’t work well for them may have other underlying issues;  we need to ask - is there another reason behind the eating disorder?

It can be difficult to diagnose autism in girls/women as ASC traits are often masked well, but with experience and spending time really listening to what the patients have to say about their difficulties will highlight differences around their experiences with numbers, senses, and communication. There is also a difficulty in diagnosing autism in patients with eating disorders as the effects on the brain of starvation can mimic some signs of autism, so it can go undetected for many years when a person is restricting food. The earlier a diagnosis can be made the better,  this can be difficult because women are very good at masking the signs of autism which can include sensory difficulties and a certain style of thinking.

More definitely needs to be done to address this overlap between people with autism and eating disorders so that the correct treatment can be given from the start.

Here is an example of a patient and her experience from an early age. There were signs that there was more to her situation than just the eating disorder, but she wasn’t diagnosed with autism till she was an adult .

Pre-school:

• Huge resistance to change and discomfort around people. Described as shy, anxious and awkward.
• Unusual sensory perception and extremely selective around food and eating – in particular the taste and texture of food. An insistence on order and symmetry.
• An early ability to play the piano, read and write. Enjoyed functional toys such as Lego, cars trains, and collected and arranged toy animals.
• Obsessed with cats and appeared to prefer animals to people.

Starting school

• Distressed when she started school and didn’t feel that she fit it. Wanted to teach herself rather than be taught.
• Completely rejected the school lunches- sensory and social issues made eating at school difficult. General anxiety and overwhelming unhappiness at school dulled her appetite.
• Experienced extreme anxiety and meltdowns at home.
• Found physical exercise very calming and enjoyable.

During Primary school

• Developed a fear of vomiting after suffering from gastroenteritis which exacerbated food avoidance and led to a fear of feeling to full after a meal.
• Developed OCD around food and vomiting.
• Started ritualistic behaviours.

During high school

• Exercised to relieve her anxiety, not to lose weight, and set herself daily exercise goals which had to be done just right - the same exercise routine at the same time of day.
• Reading nutrition charts became an enjoyable fixation that made her feel calm. She made lists of calories, grams of fat, protein and carbohydrates in all food to be eaten. Consequently, she experienced rapid, continuous, unintended and unwanted weight loss.
• Diagnosed with anorexia nervosa, but hated her weight loss, thinness and weakness and wanted to gain weight but whilst maintaining her rituals.
• Psychiatrist diagnosed OCD, anxiety and depression. Told to be more social but couldn’t relate to her peers at all and socialised better with adults .

Adulthood:

• Felt isolated and different whilst studying at University – couldn’t cope with the noise and unpredictability of other students. Isolated.
• Defaulted into ritualistic over-exercise and undereating with no desire for weight loss.
• Referred for an autism assessment and was officially diagnosed with ASC and Avoidant restrictive food intake disorder- finally received specialist help and was able to make progress with recovery.